Pearlescent pigments are increasingly used in cosmetic preparations due to their very decorative optic properties.
EP 0 912 640 B1 discloses a pearlescent pigment comprising flakes of C glass having a first coating comprising iron oxide or rutile titanium dioxide thereon. The skilled person reads from EP 0 912 640 B1 that flakes of C glass are the only glass flakes which allow to produce high quality effect pigments.
The DE 199 07 313 A1 discloses the use of shiny pigments coated with several layers in cosmetics. DE 199 07 313 A1 does not disclose pearlescent pigments based on glass flakes are mentioned.
DE 10 2005 029 647 A1 discloses cosmetic formulations providing a protection against infrared rays. The protection is mainly achieved by pearlescent pigments, which partly reflect infrared radiation. The pearlescent pigments are based on all kinds of common substrates: synthetic or natural mica, SiO2-platelets, Al2O3-platelets, glass flakes or polymer flakes.
Pearlescent pigments based on Al2O3-platelets, however, are available only in sizes below about 30 μm. Manufactures of pearlescent pigments for the cosmetic market, however, want to offer a product program of various sizes based on a single source of substrate. SiO2-flakes are expensive to produce and quite difficult to be produced in constant quality. Furthermore they exhibit extremely high colourflops which are not always demanded. Glass flakes would be the best choice as artificial substrates for effect pigments, especially for pearlescent pigments, because they can be produced reproducibly at fairly low costs and are achievable in various sizes and thicknesses.
In cosmetic formulations there is still a demand for glass flake-based pearlescent pigments with improved skin feeling and higher gloss properties.